Chickenpox vaccination is not part of the NHS childhood vaccination programme. It's only offered to individuals who are likely to come into contact with people who are particularly vulnerable to chickenpox, such as those having chemotherapy. This reduces the risk of chickenpox spreading to vulnerable people.

There's a worry that introducing chickenpox vaccination for all children could increase the risk of chickenpox and shingles in older people.

Whilst chickenpox during childhood is unpleasant, the vast majority of children recover quickly and easily. In adults, chickenpox is more severe and the risk of complications increases with age.

If a childhood chickenpox vaccination programme was introduced people would not catch chickenpox as children (as the infection would no longer circulate in areas where the majority of children had been vaccinated). This would leave unvaccinated children (there will always be a few who are unable or choose not to have the vaccine) susceptible to contracting chickenpox as adults when they are more likely to develop a more severe infection or a secondary complication, or in pregnancy when there is a risk of the infection harming the baby.

We could also see a significant increase in cases of shingles in adults. Adults who are naturally exposed to chickenpox (such as through contact with infected children) receive a natural boosting of their chickenpox antibodies which prevents the chickenpox virus (which remains dormant in the body after chickenpox infection) from reactivating in their bodies in the majority of cases and causing shingles.

If you vaccinate children against chickenpox, you lose this natural boosting so current levels of immunity in adults will drop and more shingles will occur.

Chickenpox vaccinations are provided free on the NHS where there is a clinical need, such as for healthy people with no immunity who have close contact with a person with a weakened immune system. This is to reduce the risk of the immunosuppressed person catching chickenpox, and then developing serious chickenpox complications.

Examples of children who would probably be eligible to have a chickenpox jab on the NHS include brothers and sisters of a child with leukaemia, or a child whose parent is undergoing chemotherapy.

You cannot get the chickenpox vaccine free on the NHS if you simply want to prevent your child from catching chickenpox and there are no other associated health risks.

If you spent your childhood in Wales, your GP may have noted that you had chickenpox in your medical records. If there is nothing in your notes, your GP can carry out a blood test to see if you have immunity to chickenpox.

Chickenpox in people with weakened immune systems and pregnant women without immunity can be treated with a medication called varicella zoster immunoglobulin (VZIG). VZIG contains chickenpox virus-fighting antibodies, and can reduce chickenpox symptoms, and lower the risk of complications.